Tektronix MSO56 [538/628] Trigger sources

Trigger sources

The trigger source provides the signal that triggers acquisition. Use a trigger source that is synchronized with the signal that you

are acquiring and displaying.

You can derive your trigger from the following sources:

■

Input channels. Analog input channels are the most commonly used trigger sources. You can select any of the input

channels. The channel that you select as a trigger source will function whether it is displayed or not.

■

Digital channels. These sources are available if you have a digital probe connected to a FlexChannel. You can select any

combination of digital channels.

■

Bus. This source is used to trigger a parallel bus or a serial bus. You can include any combination of analog, math, or digital

channels to build a parallel bus, or use any channel as a component in a serial bus.

Trigger types

The available trigger types include:

Edge. This is the simplest and most commonly used trigger type, used with both analog and digital signals. An edge trigger event

occurs when the trigger source passes through a specified voltage level in the specified direction (rising or falling signal voltage).

When the edge trigger source is set to AC Line, the instrument uses the instrument's AC power line signal to generate a trigger

based on the power line frequency. The 6MSO series and the MSO58LP instruments also have an AUX In connector that is

available as another source for the Edge trigger.

Pulse Width. Trigger on pulses that are inside or outside a specified time range. Can trigger on positive or negative pulses.

Timeout. Trigger when no edge transition is detected within a specified time.

Runt. Use Runt trigger to trigger on a pulse amplitude that crosses one threshold but fails to cross a second threshold before

recrossing the first. Can detect positive or negative runts, or only those wider than a specified width. These pulses can also be

qualified by the logical state of other channels.

Window. Use the Window trigger to trigger when the input signal is enters or leaves a window set by two threshold levels. You

can further qualify the trigger event in terms of time by using the Trigger When controls, or by using the logical state of other

channels by using the Logic Qualification control.

Logic. These are special-purpose triggers that are primarily used with digital logic signals. Logic triggers are available on the

main (A) and B event triggers.

Setup & Hold. Trigger when a logic input changes state inside the setup and hold times relative to the clock. This type triggers

on a setup and hold violation.

Rise/Fall Time. Trigger on pulse edges that traverse between two thresholds at faster or slower rates than the specified time.

The pulse edges can be positive or negative.

Sequence. Use the A Trigger Event with the B Trigger Event to capture complex data.

Bus. This trigger is used with both analog and digital signals to set up parallel and serial buses. A bus trigger event occurs when

the instrument detects a bus pattern that you set in a bus trigger configuration menu. You must add a bus to the Waveform view

before you can set the trigger parameters for that bus.

Trigger concepts

508 4/5/6 Series MSO Help